US20200195105A1 - Rotor and rotor manufacturing method - Google Patents
Rotor and rotor manufacturing method Download PDFInfo
- Publication number
- US20200195105A1 US20200195105A1 US16/701,624 US201916701624A US2020195105A1 US 20200195105 A1 US20200195105 A1 US 20200195105A1 US 201916701624 A US201916701624 A US 201916701624A US 2020195105 A1 US2020195105 A1 US 2020195105A1
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- United States
- Prior art keywords
- rotor
- iron core
- core material
- rotor core
- permanent magnets
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
- H02K1/22—Rotating parts of the magnetic circuit
- H02K1/27—Rotor cores with permanent magnets
- H02K1/2706—Inner rotors
- H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
- H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
- H02K1/22—Rotating parts of the magnetic circuit
- H02K1/27—Rotor cores with permanent magnets
- H02K1/2706—Inner rotors
- H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
- H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
- H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
- H02K1/278—Surface mounted magnets; Inset magnets
- H02K1/2781—Magnets shaped to vary the mechanical air gap between the magnets and the stator
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
- H02K1/22—Rotating parts of the magnetic circuit
- H02K1/27—Rotor cores with permanent magnets
- H02K1/2706—Inner rotors
- H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
- H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
- H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
- H02K1/276—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
- H02K1/2766—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] having a flux concentration effect
- H02K1/2773—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] having a flux concentration effect consisting of tangentially magnetized radial magnets
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K13/00—Structural associations of current collectors with motors or generators, e.g. brush mounting plates or connections to windings; Disposition of current collectors in motors or generators; Arrangements for improving commutation
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
- H02K15/02—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
- H02K15/03—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies having permanent magnets
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K3/00—Details of windings
- H02K3/46—Fastening of windings on the stator or rotor structure
- H02K3/50—Fastening of winding heads, equalising connectors, or connections thereto
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
- H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
- H02K5/163—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields radially supporting the rotary shaft at only one end of the rotor
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
- H02K2201/06—Magnetic cores, or permanent magnets characterised by their skew
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
- H02K2201/09—Magnetic cores comprising laminations characterised by being fastened by caulking
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/64—Electric machine technologies in electromobility
Definitions
- the present invention relates to a rotor and a rotor manufacturing method.
- motor torque pulsations are a primary cause of noise and vibration.
- One primary factor in torque pulsation is cogging torque.
- a rotor with a step skew structure is used to reduce cogging torque, as disclosed in JP 2014-236592 A, for example.
- the rotor core disclosed in JP 2014-236592 A has a step skew structure formed by laminating iron core material and a plurality of stepped cores, which have a plurality of permanent magnets provided around the iron core material, shifted by an amount corresponding to a skew angle.
- a rotor is configured by providing a through-hole, into which a rotating shaft is inserted, in the iron core material constituting the rotor core and by inserting the rotating shaft into the through-hole.
- a key protruding in a radially inward direction from the inner peripheral surface of the rotor core is provided, and a plurality of key grooves for fixing the rotor core, each corresponding to the respective stepped cores, are provided on the outer peripheral surface of the rotating shaft in positions shifted by an amount corresponding to a skew angle.
- the foregoing stepped cores can be formed by using adhesive to attach a plurality of permanent magnets around a cylindrical iron core material having a through-hole into which a rotating shaft is inserted, for example.
- the rotor core can be formed by laminating the plurality of stepped cores and press-fitting the rotating shaft into the through-hole by applying a load in the lamination direction.
- the end faces of the stepped cores are not necessarily flat due to dimensional errors of the iron core material and permanent magnets, respectively, rather, the iron core material may protrude further than the permanent magnets, or the permanent magnets may protrude further than the iron core material.
- an object of the present invention is to provide a rotor and a rotor manufacturing method with which it is possible to obtain a rotor of stable quality.
- a rotor in order to achieve the foregoing object, includes a drive shaft, a first rotor core unit, and a second rotor core unit.
- the first rotor core unit includes a first iron core material having a through-hole into which the drive shaft is inserted, a plurality of first permanent magnets provided on the first iron core material, and a first reference surface at which the first iron core material and first permanent magnets are flush or at which the first iron core material protrudes further than the permanent magnets.
- the second rotor core unit includes a second iron core material having a through-hole into which the drive shaft is inserted, a plurality of second permanent magnets arranged on the side of the second iron core material, and a second reference surface at which the second iron core material and second permanent magnets are flush or at which the second iron core material protrudes further than the permanent magnets, the second rotor core unit being laminated in an axial direction on the first rotor core unit such that the first reference surface and the second reference surface contact each other, and being positioned shifted through a predetermined angle in the rotation direction of the drive shaft from the first rotor core unit.
- a rotor manufacturing method includes forming an iron core material by laminating a plurality of rotor plates having a through-hole into which a drive shaft is inserted; attaching permanent magnets to the iron core material to form a rotor core unit having a reference surface at which the iron core material and the permanent magnets are flush or at which the iron core material protrudes further than the permanent magnets; and placing two of the rotor core units in an axial direction such that the reference surfaces thereof lie opposite each other, shifted in a circumferential direction, causing the reference surfaces of the two rotor core units to abut each other, and press-fitting the drive shaft into the through-hole by applying a load to the two rotor core units.
- FIG. 1 is an exploded perspective view illustrating a configuration example of a rotating electrical device in which a rotor according to an embodiment of the present invention is installed;
- FIG. 2 is an essential part cross-sectional view of the rotating electrical device
- FIG. 3 is a perspective view of the rotor according to an embodiment of the present invention.
- FIG. 4 is a perspective view of a rotor core unit constituting the rotor
- FIGS. 5A and 5B are plan views of a rotor plate constituting an iron core material which constitutes the rotor core unit;
- FIG. 6 is a plan view of when two of the rotor plates are stacked together with the surface and back sides thereof oriented in opposite directions;
- FIGS. 7A to 7C are assembly process views illustrating steps for assembling the rotor core unit
- FIG. 8 is a schematic cross-sectional view of a press fitting apparatus which is a view serving to illustrate a step of press-fitting a drive shaft in manufacturing the rotor core;
- FIG. 9 is a partial perspective view of the press fitting apparatus which is a view serving to illustrate a drive shaft press-fitting step
- FIGS. 10A and 10B are schematic cross-sectional views of the rotor core unit
- FIGS. 11A and 11B are schematic cross-sectional views of the rotor core
- FIGS. 12A and 12B are a plan view of a rotor plate according to another embodiment and a plan view when two of the rotor plates are stacked together with the surface and back sides thereof oriented in opposite directions;
- FIGS. 13A and 13B are diagrams to illustrate a method of manufacturing a rotor core which is a comparative example.
- a rotating electrical device 100 which includes a rotor according to one embodiment of the present invention is used as an automobile electric steering apparatus, for example, and is configured as a motor which applies a steering auxiliary force to a steering shaft.
- FIG. 1 is an exploded perspective view illustrating a configuration example of rotating electrical device 100 according to one embodiment of the present invention
- FIG. 2 is an essential part cross-sectional view of rotating electrical device 100 .
- the rotating electrical device 100 has a casing 10 , a component package 20 , a motor 30 , a busbar unit 40 , a bearing holder 50 , and a press-fit ring 60 .
- the casing 10 is formed with a cylinder-shaped (cylindrical) outline having an opening 11 and a bottom portion 12 opposite the opening 11 .
- the casing 10 is typically configured from a metal material such as aluminum die-cast or aluminum, and, as illustrated in FIG. 2 , accommodates the motor 30 , the busbar unit 40 , and the like.
- the casing 10 is provided between the bottom portion 12 and step portion 15 and has a motor chamber 10 M (see FIG. 2 ) for accommodating the rotor 32 , described subsequently.
- the component package 20 is held at the top end of the casing 10 above the motor 30 , busbar unit 40 , and bearing holder 50 .
- the component package 20 has a component mounting substrate 21 and a heat sink 23 .
- the component mounting substrate 21 of the present embodiment is a circuit board which includes various electronic devices (not illustrated) constituting an electronic control unit (ECU) of an electric power steering (EPS) apparatus.
- the electronic devices include a central processing unit (CPU), a memory, and the like.
- the component mounting substrate 21 is fixed to a heat sink (lid portion) 23 via a plurality of screw portions (not illustrated).
- the heat sink 23 constitutes a lid portion which hermetically seals the interior of the casing 10 by being fitted to the opening 11 in the casing 10 via a seal ring S (see FIG. 2 ).
- an external connection terminal 23 a which electrically interconnects the component mounting substrate 21 and a power-supply unit which is not illustrated, is provided on the upper face of the heat sink 23 .
- the perimeter of the heat sink 23 is provided with a plurality of brackets 23 b having a screw insertion hole, and is fastened with screws to a plurality of fixing brackets 14 provided on the perimeter of the opening 11 in the heat sink 23 via the brackets 23 b.
- the motor 30 is accommodated in the motor chamber 10 M in the casing 10 as illustrated in FIG. 2 and has a stator 31 and a rotor 32 .
- the stator 31 includes a plurality of teeth (stator cores) which are arranged in an annular shape inside the casing 10 and coils (stator coils) which are wound around each of the plurality of teeth.
- the teeth are formed of a magnetic material and configured from a laminated body of a plurality of magnetic, rigid plates, for example.
- the stator 31 is fixed to the casing 10 by being fitted to the inner circumference of the casing 10 .
- both ends (not illustrated) of the coils are electrically connected to the busbar unit 40 .
- the rotor 32 has a drive shaft (rotating shaft) 321 which rotates about an axis (Z axis), and a rotor core 322 which is attached to the drive shaft 321 .
- the drive shaft 321 is disposed along the axial center of the casing 10 and press-fitted into a through-hole formed in the center of the rotor core 322 .
- the drive shaft 321 is rotatably supported in the casing 10 via a bearing B 1 (first bearing) and a bearing B 2 (second bearing).
- the rotor core 322 has a plurality of magnetic poles arranged in a circumferential direction.
- the rotor 32 is disposed inside the stator 31 and causes the drive shaft 321 to rotate on its axis under electromagnetic action with the stator 31 .
- One end (the lower end in FIGS. 1 and 2 ) of the drive shaft 321 passes through the bottom portion 12 of the casing 10 and has a gear portion 323 at its tip.
- the gear portion 323 meshes with a mating gear (not illustrated) linked to the steering shaft and transmits the rotation of the drive shaft 321 to the steering shaft.
- One bearing B 1 (first bearing) is attached to the bottom portion 12 of the casing 10 and rotatably supports one end of the drive shaft 321 .
- the other bearing B 2 (second bearing) rotatably supports the other end of the drive shaft 321 .
- the bearing B 2 is disposed between the rotor core 322 and the heat sink 23 and is fixed to the casing 10 via the bearing holder 50 .
- the bearing holder 50 will be described in detail subsequently.
- the busbar unit 40 has a plurality of busbars 41 formed of a conductive material and an electrically insulated busbar holder 42 which encloses the busbars 41 (see FIG. 2 ).
- the busbar holder 42 is configured from an annular molded body, and the plurality of busbars 41 include a plurality of connecting terminals 41 a which protrude radially outward from the outer peripheral surface of the busbar holder 42 , and a plurality of power supply terminals 41 b which extend in an axial direction from the upper surface of the busbar holder 42 and which correspond to a U phase, V phase, and W phase, respectively (see FIG. 1 ).
- the busbar unit 40 is disposed inside the casing 10 and is connected to the stator coils concentrically with the drive shaft 321 .
- the plurality of connecting terminals 41 a are electrically connected to one end of the U-phase, V-phase and W-phase stator coils, respectively, and the plurality of power supply terminals 41 b are electrically connected to a connector component 22 on the component mounting substrate 21 which is fixed to the heat sink 23 (see FIG. 2 ).
- the press-fit ring 60 is annular, as illustrated in FIG. 1 .
- the press-fit ring 60 is press-fit via the opening 11 into the casing 10 so as to sandwich the bearing holder 50 in the Z axis direction in conjunction with the step portion 15 .
- the press-fit ring 60 has an outer peripheral surface 60 A which is press-fit to the inner peripheral surface of the opening 11 , and a second support face 60 B which abuts the perimeter of the bearing holder 50 .
- the press-fit ring 60 is formed of the same material as the casing 10 (aluminum die-cast or aluminum, or the like) or a material with a linear expansion coefficient on the order of the casing 10 (brass or a magnesium alloy, for example).
- the bearing holder 50 serves to align and hold bearing B 2 within the casing 10 , and is configured from a metallic-plate press-molded body.
- the bearing holder 50 according to the present embodiment is manufactured by deep-drawing and bending a metallic plate into a solid body shape.
- the bearing holder 50 is roughly disc-shaped, and provided in the center thereof is an axial hole through which the drive shaft 321 passes.
- a bearing holding portion 502 for press-fitting and holding the second bearing B 2 is provided in order to enclose the axial hole.
- the bearing holding portion 502 integrally holds the bearing B 2 by means of a joining or fitting action with the outer race of the bearing B 2 .
- an integral join with bearing B 2 may also be obtained by caulking the open lower end portion of the bearing holding portion 502 .
- the bearing holder 50 may be configured from a magnetic material or may be configured from a nonmagnetic material. As a result of the bearing holder 50 being configured from a magnetic material, a shielding effect whereby the electronic component on the component mounting substrate 21 is protected from the effects of an electromagnetic field generated by the stator 31 and the rotor 32 is obtained.
- Such materials include SPCC (steel plate cold commercial), for example, but obviously is not limited to or by SPCC.
- FIG. 3 is a perspective view of the rotor 32 .
- FIG. 4 is a perspective view of a rotor core unit 63 constituting the rotor 32 .
- the rotor 32 of the present embodiment is a rotor with a step skew structure.
- the rotor 32 is configured by laminating a plurality of independent rotor core units 63 which are shifted through predetermined angles in the circumferential direction.
- the rotor 32 has a drive shaft 321 and a rotor core 322 .
- An insertion hole 322 a through which the drive shaft 321 passes is provided in the center of an approximately cylindrical rotor core 322 .
- the rotor core 322 is configured by laminating a plurality, two in the present embodiment, of independent rotor core units 63 .
- a rotor core unit 63 which is positioned on a lower level is called the lower rotor core unit 63 a
- a rotor core unit 63 which is positioned on an upper level is called the upper rotor core unit 63 b.
- the lower rotor core unit 63 a which constitutes a first rotor core unit, has an aspect obtained by rotating (or inverting), in a vertically opposing direction, the upper rotor core unit 63 b , which constitutes a second rotor core unit. Otherwise, when the lower rotor core unit 63 a and upper rotor core unit 63 b have the same configuration and there is no particular need to describe the upper and lower rotor core units distinctly, same are sometimes simply referred to as the rotor core units 63 .
- the first iron core material is called lower iron core material 8 a
- the second iron core material is called upper iron core material 8 b
- the first permanent magnet is called lower permanent magnet 9 a
- the second permanent magnet is called upper permanent magnet 9 b
- same may be called the iron core material 8 and permanent magnets 9 .
- the rotor core units 63 have a roughly cylindrical shape, and include a reference surface 61 , and an opposite surface 62 which lies opposite the reference surface 61 (see FIG. 8 , for example).
- the lower rotor core unit 63 a and upper rotor core unit 63 b are laminated such that the reference surfaces 61 thereof abut each other.
- the lower rotor core unit 63 a is disposed shifted, relative to the upper rotor core unit 63 b , through a predetermined angle (skew angle) in the rotation direction of the drive shaft 321 (in the circumferential direction of the rotor core unit).
- the cogging torque can accordingly be reduced.
- the foregoing shift is 12 degrees in the present embodiment, the present invention is not limited to or by this shift.
- the skew angle is suitably configured according to the shape and number of permanent magnets, and the like.
- a reference sign 61 a is sometimes assigned to the reference surface of the lower rotor core unit 63 a which constitutes a first reference surface
- a reference sign 61 b is sometimes assigned to the reference surface of the upper rotor core unit 63 b which constitutes a second reference surface
- the opposite surface 62 opposite the reference surface 61 is sometimes described hereinbelow by assigning a reference sign 62 a to the opposite surface of the lower rotor core unit 63 a and by assigning a reference sign 62 b to the opposite surface of the upper rotor core unit 63 b.
- FIG. 5A is a plan view of a steel sheet 81 which is a rotor plate constituting the iron core material 8 .
- FIG. 5B is a plan view of when the surface and back sides of the steel sheet 81 in FIG. 5A are oriented in opposite directions.
- FIG. 6 is a plan view of when two steel sheets 81 are stacked together with the surface and back sides thereof oriented in opposite directions.
- the rotor core units 63 have an iron core material 8 which is fixed to the outer periphery of the drive shaft 321 and rotates together with the drive shaft 321 , and a plurality of permanent magnets 9 which are attached at equal intervals around the outer periphery of the iron core material 8 .
- Six permanent magnets 9 are provided in the present embodiment.
- the iron core material 8 is configured by laminating a plurality of the steel sheets 81 illustrated in FIG. 5A , as illustrated in FIG. 2 .
- the steel sheets 81 have a through-hole 84 in the center of which the drive shaft 321 is inserted, a first alignment hole 82 , and a second alignment hole 83 . All of the holes have a circular planar shape.
- the iron core material 8 is formed by laminating the plurality of steel sheets 81 such that the respective through-holes 84 , first alignment holes 82 and second alignment holes 83 are stacked on top of each other.
- the respective through-holes 84 are contiguous, and the through-hole 841 (see FIG. 4 ) of the iron core material 8 is formed.
- a reference sign 841 a is assigned to the through-hole provided in the iron core material 8 a of the lower rotor core unit 63 a
- a reference sign 841 b is assigned to the through-hole provided in the iron core material 8 b of the upper rotor core unit 63 b (see FIG. 9 ).
- the through-holes 841 a and 841 b of the iron core material 8 of the respective rotor core units 63 a and 63 b are contiguous, and an insertion hole 322 a in which the drive shaft 321 is inserted is formed.
- the respective first alignment holes 82 are contiguous, and a first alignment hole 821 , which passes through the iron core material 8 , is formed.
- the respective second alignment holes 83 of the laminated plurality of steel sheets 81 are contiguous, and a second alignment hole 831 , which passes through the iron core material 8 , is formed (see FIG. 4 ).
- Reference signs 821 a and 831 a are assigned to the first alignment hole and second alignment hole, respectively, which are provided in the iron core material 8 a of the lower rotor core unit 63 a .
- Reference signs 821 b and 831 b are assigned to the first alignment hole and second alignment hole, respectively, which are provided in the iron core material 8 b of the upper rotor core unit 63 b (see FIG. 9 ).
- the foregoing alignment holes are sometimes referred to as the first alignment hole 821 and the second alignment hole 831 .
- the steel sheets 81 have an approximately circular shape.
- Six protrusions 85 are provided at equal intervals on the periphery of the steel sheets 81 .
- the iron core material 8 When the iron core material 8 is formed by stacking together a plurality of the steel sheets 81 , six linear protrusions which extend parallel to the axial direction of the six drive shafts 321 are formed by the protrusions 85 on the side of the cylindrical iron core material 8 . Furthermore, permanent magnets 9 are arranged in the gaps formed between the adjacent linear protrusions.
- the first alignment hole 82 and second alignment hole 83 both have planar shapes which are circles of the same diameter.
- the first alignment hole 82 and second alignment hole 83 are not positioned on the same circumferences centered on the steel sheet 81 , rather, same are located at different distances from the center of the steel sheet 81 .
- first alignment hole 82 and second alignment hole 83 both have a circular shape with a diameter which is 1.5 mm in size, and the distance between the center of the first alignment hole 82 and the center of the steel sheet 81 is 8 mm, and the distance between the center of the second alignment hole 83 and the center of the steel sheet 81 is 7.75 mm.
- an angle of 128° is formed between a straight line joining the center of the steel sheet 81 to the first alignment hole 82 and a straight line joining the center of the steel sheet 81 to the second alignment hole 83 .
- the numerical values of these dimensions are not limited to the numerical values appearing here.
- the steel sheet 81 has a first face 811 and a second face 812 which are opposite each other.
- FIG. 5A is a plan view of when the first face 811 is made the upper surface.
- FIG. 5B is a plan view of when the second face 812 is made the upper surface.
- first alignment hole 82 and second alignment hole 83 are formed to not have the same shape when the surface and back sides of the steel sheet 81 are oriented in opposite directions. Furthermore, the circular through-hole 84 which is provided in the center of the steel sheets 81 is provided to afford coincidence when two steel sheets 81 are stacked together with the surface and back sides thereof oriented in opposite directions.
- a steel sheet 81 a is a steel sheet for when the second face 812 illustrated in FIG. 5B is made the upper surface.
- a steel sheet 81 b is a steel sheet for when the first face 811 illustrated in FIG. 5A is made the upper surface.
- the steel sheet 81 a is located below the steel sheet 81 b.
- FIG. 6 illustrates the positional relationship, in the rotor 32 illustrated in FIG. 3 , between a steel sheet 81 which constitutes the iron core material 8 b of the upper rotor core unit 63 b and the steel sheet 81 which constitutes the iron core material 8 a of the lower rotor core unit 63 a .
- the lower rotor core unit 63 a and upper rotor core unit 63 b are arranged shifted through a predetermined angle, which is 12° in the present embodiment, in the direction of rotation of the drive shaft 321 .
- the steel sheet 81 constituting iron core material 8 b of the upper rotor core unit 63 b corresponds to the steel sheet 81 b on the upper surface of which the first face 811 is located.
- the steel sheet 81 constituting iron core material 8 a of the lower rotor core unit 63 a corresponds to the steel sheet 81 a on the upper surface of which the second face 812 is located.
- reference signs 82 b and 83 b are assigned to the first and second alignment holes, respectively, in the steel sheet 81 b which is disposed on the upper side
- reference signs 82 a and 83 a are assigned to the first and second alignment holes, respectively, in the steel sheet 81 a which is disposed on the lower side.
- the alignment holes 821 and 831 do not coincide with each other.
- the rotor core units 63 may have seven or more permanent magnets arranged side by side in a circumferential direction or may have any number, from two to five, of permanent magnets.
- the rotor 32 is formed by press-fitting and securing the drive shaft 321 in the insertion hole 322 a in the rotor core 322 .
- the surface, of the drive shaft 321 which corresponds to the insertion hole 322 a (configuration denoted by the reference sign 321 a in FIG. 8 , described subsequently) is knurled, and the surface has a textured shape.
- the diameter of the insertion hole 322 a is slightly smaller than the diameter of the drive shaft 321 .
- the rotor core 322 is fixed to the drive shaft 321 by press-fitting the drive shaft 321 in the insertion hole 322 a.
- the lower rotor core unit 63 a and upper rotor core unit 63 b are arranged such that the reference surface 61 a and reference surface 61 b abut each other.
- the reference surfaces 61 are flat surfaces.
- flat surfaces also include, in addition to an aspect where the end face of the iron core material 8 and the end faces of the permanent magnets 9 are completely flush, an aspect in which, due to an error during assembly of the rotor core unit 63 , the end face of the iron core material 8 protrudes 0.2 mm or less in the axial direction further than the end faces of the permanent magnets 9 .
- the rotor 32 is mainly manufactured through a step of assembling the rotor core units 63 and a press-fitting step of press-fitting the drive shaft 321 inside the two laminated rotor core units 63 . Each step will be described hereinbelow.
- FIGS. 7A to 7C are views of the step of assembling the rotor core units 63 .
- the assembly jig 200 is mounted on a flat surface.
- the jig 200 is used for alignment so that, when forming the iron core material 8 obtained by laminating a plurality of steel sheets 81 , the plurality of steel sheets 81 are not laminated with a skew. Furthermore, the jig 200 is used for alignment so that the respective end faces of the iron core material 8 and permanent magnets 9 are aligned upon fastening the plurality of permanent magnets 9 to the periphery of the iron core material 8 .
- the jig 200 has a workbench 202 which has a flat working surface 201 , and two alignment pins 212 and 213 which are fixed to the workbench 202 .
- the alignment pin 212 is provided to correspond to the alignment hole 82 of the steel sheets 81
- the alignment pin 213 is provided to correspond to the alignment hole 83 .
- the steel sheets 81 are mounted on the workbench 202 by passing the corresponding alignment pins 212 and 213 provided in the jig 200 through the alignment holes 82 and 83 , respectively, of the steel sheets 81 . Accordingly, the steel sheets 81 are mounted such that the first face 811 of the steel sheets 81 is the upper surface, and the second face 812 is positioned on the working surface 201 side.
- a predetermined number of steel sheets 81 are laminated on the jig 200 .
- the alignment holes 82 and 83 are provided in the steel sheets 81 so as to not coincide with each other when two steel sheets 81 are stacked together with the surface and back sides thereof oriented in opposite directions.
- the steel sheets 81 can be laminated reliably, with the first face 811 serving as the upper surface, by placing the steel sheets 81 according to the alignment pins 212 and 213 provided on the jig 200 .
- the steel sheets 81 can be laminated reliably such that the second face 812 is positioned on the working surface 201 side, even when the steel sheets 81 are to be mounted with the surface and back sides thereof oriented in opposite directions, because the alignment pins 212 and 213 cannot pass through the alignment holes 82 and 83 .
- the iron core material 8 is formed by laminating and stacking a predetermined number of steel sheets 81 .
- the iron core material 8 has a through-hole 841 , a first alignment hole 821 , and a second alignment hole 831 , which each pass through the iron core material 8 .
- the permanent magnets 9 are fastened to the periphery of the iron core material 8 in a state where the iron core material 8 is mounted on the workbench 202 . Thereupon, by sticking the permanent magnets 9 to the iron core material 8 so that one end face of the permanent magnets 9 contacts the working surface 201 , one end face of the permanent magnets 9 and one end face of the iron core material 8 can be aligned on the same surface.
- the rotor core units 63 are thus assembled as illustrated in FIG. 7C .
- the surface, of the rotor core unit 63 , which contacts the working surface 201 is reference surface 61
- the surface opposite the reference surface 61 is opposite surface 62 .
- the reference surface 61 is a flat surface.
- flat surfaces also include, in addition to an aspect where the second face 812 of the steel sheet 81 in the lowest position which constitutes the iron core material 8 and one end face of the permanent magnets 9 are completely flush, an aspect in which, due to an error during assembly of the rotor core unit 63 , one end face of the iron core material 8 (corresponds here to the second face 812 of the steel sheet 81 in the lowest position which constitutes the iron core material 8 during assembly) protrudes 0.2 mm or less further than the one end face of the permanent magnets 9 .
- a drive shaft press-fitting step in which two rotor core units 63 , assembled as mentioned earlier, are laminated and the drive shaft 321 is press-fit will be described next using FIGS. 8 and 9 .
- FIG. 8 is a schematic cross-sectional view of a press fitting apparatus 7 which is a view serving to illustrate a driving shaft press-fitting step.
- the through-hole 841 and alignment holes 821 and 831 provided in each of the rotor core units 63 a and 63 b are omitted from the illustration of FIG. 8 in order to make the drawing clearer.
- FIG. 9 is a partial perspective view of the press fitting apparatus 7 .
- FIG. 9 is a diagram illustrating the positional relationships between alignment holes 821 a , 831 a , 821 b , and 831 b of each of the rotor core units 63 a and 63 b , and alignment pins 7122 , 7123 , 7222 , and 7223 provided in each of the support bases 712 and 722 .
- the press fitting apparatus 7 has a lower support portion 71 constituting a first support portion and an upper support portion 72 .
- the lower support portion 71 has a lower pedestal 711 and a lower support base 712 constituting a first support base.
- the lower pedestal 711 has a larger planar shape than the lower support base 712 and supports the lower support base 712 .
- the lower support base 712 is installed on the lower pedestal 711 .
- a first alignment support pin 7122 and a second alignment support pin 7123 are provided on the lower support base 712 .
- the lower support base 712 is configured to enable the lower rotor core unit 63 a to be installed and mainly supports the iron core material 8 a part of the lower rotor core unit 63 a.
- Insertion holes 7111 and 7121 which are through-holes enabling insertion of the drive shaft 321 , are provided in the lower pedestal 711 and lower support base 712 , respectively.
- the first alignment support pin 7122 and second alignment support pin 7123 which are provided on the lower support base 712 are arranged in positions enabling insertion into the first alignment hole 821 a and the second alignment hole 831 a , respectively, of the lower rotor core unit 63 a on the lower surface of which the opposite surface 62 a is located and on the upper surface of which reference surface 61 a is located.
- the upper support portion 72 has an upper pedestal 721 and an upper support base 722 constituting a second support base.
- the upper pedestal 721 has a larger planar shape than the upper support base 722 and supports the upper support base 722 .
- the upper support base 722 is installed on the upper pedestal 721 .
- a first alignment support pin 7222 and a second alignment support pin 7223 are provided on the upper support base 722 .
- the upper support base 722 is configured to enable the upper rotor core unit 63 b to be installed and mainly supports an iron core material 8 b part of the upper rotor core unit 63 b.
- Insertion holes 7211 and 7221 which enable insertion of the drive shaft 321 , are provided in the upper pedestal 721 and upper support base 722 , respectively.
- Insertion hole 7221 which is provided in the upper support base 722 , is a through-hole
- insertion hole 7211 which is provided in the upper pedestal 721 , is an insertion hole with a bottom portion prescribing an insertion limit of the drive shaft 321 .
- the first alignment support pin 7222 and second alignment support pin 7223 which are provided on the upper support base 722 are arranged in positions enabling insertion into the first alignment hole 821 b and the second alignment hole 831 b , respectively, of the upper rotor core unit 63 b on the upper surface of which the opposite surface 62 b is located and on the lower surface of which the reference surface 61 b is located.
- the positions of the first and second alignment support pins 7222 and 7223 of the upper support base 722 coincide with the positions of the first and second alignment support pins 7122 and 7123 when the lower support base 712 has been vertically inverted and rotated in a circumferential direction in the drawing.
- the upper support base 722 and lower support base 712 are arranged such that the upper rotor core unit 63 b and lower rotor core unit 63 a are shifted in a circumferential direction through a skew angle.
- the rotor core unit 63 b assembled in the foregoing assembly step can be installed on the upper support base 722 by making the opposite surface 62 b the upper surface and the reference surface 61 b the lower surface.
- the rotor core unit 63 a assembled in the foregoing assembly step can be installed on the lower support base 712 by making the opposite surface 62 a the lower surface and the reference surface 61 a the upper surface.
- the rotor core units can be arranged in the press fitting apparatus 7 without confirming the reference surfaces 61 , and workability improves. Moreover, because two rotor core units can be laminated such that the reference surfaces 61 thereof reliably lie opposite each other, it is possible to obtain a rotor 32 of a quality which is always stable.
- FIGS. 8 and 9 A step of press-fitting the drive shaft 321 which employs the foregoing press fitting apparatus 7 will be described next using FIGS. 8 and 9 .
- the lower rotor core unit 63 a is installed on the lower support base 712 such that the alignment pins 7122 and 7123 are inserted into the respective alignment holes 821 a and 831 a.
- the lower rotor core unit 63 a is installed such that reference surface 61 a is located on an upper side and the opposite surface 62 a is located on a lower side.
- the upper rotor core unit 63 b is installed on the upper support base 722 such that the alignment pins 7222 and 7223 are inserted into the respective alignment holes 182 b and 183 b.
- the upper rotor core unit 63 b is installed such that reference surface 61 b is located on a lower side and the opposite surface 62 b is located on an upper side.
- the upper rotor core unit 63 b and lower rotor core unit 63 a are arranged such that the reference surfaces 61 thereof lie opposite each other.
- the drive shaft 321 is provisionally inserted in the lower rotor core unit 63 a .
- the drive shaft 321 is provisionally inserted as a result of an area below the knurled surface 321 a passing through the respective insertion holes in the lower rotor core unit 63 a , the lower support base 712 , and the lower pedestal 711 .
- the upper support portion 72 is moved downward and the lower support portion 71 is moved upward, thereby press-fitting the drive shaft 321 into the upper rotor core unit 63 b and the lower rotor core unit 63 a .
- a load is applied to the upper rotor core unit 63 b and lower rotor core unit 63 a during the press fitting of the drive shaft 321 .
- the drive shaft 321 is press-fit into the upper rotor core unit 63 b and lower rotor core unit 63 a , thereby forming the rotor 32 .
- the opposite surface 62 which lies opposite the reference surface 61 which is a flat surface is designed to be a flat surface, but unevenness can inevitably be generated as a result of intrinsic dimensional errors, or the like, in the iron core material 8 and permanent magnets 9 .
- the iron core material 8 may protrude further than the other end face of the permanent magnet 9 and, as illustrated in FIG. 10B , the other end face of the permanent magnet 9 may protrude further than the iron core material 8 .
- unevenness can inevitably be generated in the opposite surface 62 relative to the reference surface 61 which is a flat surface.
- the unevenness which is generated in the opposite surface 62 of the rotor core unit 63 is unevenness where the difference between the permanent magnets 9 and iron core material 8 is less than 1 mm, for example, and, at first glance, it is difficult to identify which of the surfaces of the rotor core unit 63 is the reference surface 61 .
- the drive shaft 321 is press-fit by applying a load in an axial direction to the two laminated rotor core units 63 .
- the rotor 32 is manufactured by using the rotor core unit 63 , illustrated in FIG. 10B , in which the permanent magnets 9 protrude further than the iron core material 8 at the opposite surface 62
- the press-fitting step is performed with the opposite surfaces 62 of two rotor core units 63 a and 63 b arranged opposite each other, as illustrated in FIG. 13B , a load is applied in an axial direction to the two rotor core units 63 a and 63 b , and the permanent magnets 9 collide with each other.
- the permanent magnets 9 are formed by fragile, sintered bodies, and hence the permanent magnets 9 are damaged in the press-fitting step.
- two rotor core units 63 a and 63 b are laminated such that the reference surfaces 61 thereof, which are flat surfaces, are reliably arranged opposite each other and abut each other, it is possible to manufacture the rotor 32 stably without the permanent magnets 9 colliding with each other and being damaged.
- the upper rotor core unit 63 b and lower rotor core unit 63 a which constitute the rotor 32 , can be assembled by means of the same assembly jig 200 , there is no need to assemble upper and lower rotor core units by means of separate assembly jigs, and hence workability is favorable.
- the rotor 32 of the present embodiment includes a drive shaft 321 ; a lower rotor core unit (first rotor core unit) 63 a which includes a lower iron core material (first iron core material) 8 a having a through-hole 841 a into which the drive shaft 321 is inserted, a plurality of lower permanent magnets (first permanent magnets) 9 a provided on the lower iron core material (first iron core material) 8 a , and a first reference surface 61 a at which the lower iron core material (first iron core material) 8 a and lower permanent magnets (first permanent magnets) 9 a are flush or at which the lower iron core material (first iron core material) 8 a protrudes further than the lower permanent magnets (first permanent magnets) 9 a ; and an upper rotor core unit (second rotor core unit) 63 b which includes an upper iron core material (second iron core material) 8 b having a through-hole 841 b into which the drive shaft 321 is inserted, a plurality of
- the method of manufacturing the rotor 32 of the present embodiment includes: forming an iron core material 8 by laminating a plurality of steel sheets (rotor plates) 81 having a through-hole 841 into which a drive shaft 321 is inserted; attaching permanent magnets 9 to the iron core material 8 to form a rotor core unit 63 having a reference surface 61 at which the iron core material 8 and the permanent magnets 9 are flush or at which the iron core material 8 protrudes further than the permanent magnets 9 ; and placing two of the rotor core unit 63 in an axial direction such that the reference surfaces 61 thereof lie opposite each other, shifted in a circumferential direction, causing the reference surfaces 61 of the two rotor core units 63 to abut each other, and press-fitting the drive shaft 321 into the through-hole 841 by applying a load to the two rotor core units 63 .
- the rotor 32 is formed by way of lamination such that the reference surfaces 61 of the two rotor core units 63 abut each other, and therefore the permanent magnets 9 of each rotor core unit 63 do not collide and are not damaged, thereby enabling a rotor 32 of stable quality to be obtained.
- the first alignment hole 82 and second alignment hole 83 which are at different distances from the center of the steel sheet 81 , are provided as the alignment holes provided in the steel sheets 81 , the present invention is not limited to such an example.
- the alignment holes may be provided such that the alignment holes do not coincide with each other when two steel sheets are stacked together with the surface and back sides thereof oriented in opposite directions.
- a first alignment hole 182 and a second alignment hole 183 which are circles of different diameters, are provided, and the first alignment hole 182 and second alignment hole 183 may be provided such that there is no point symmetry positional relationship, in which the center of the steel sheets 181 is the center of symmetry, therebetween.
- the first alignment hole 182 and second alignment hole 183 may be in positions which are the same distance from the center or may be in different positions.
- different thicknesses may be used for the two alignment pins provided on the assembly jig which is used when assembling the rotor core units and for the two alignment pins provided on each support base used in the press fitting apparatus, respectively.
- first alignment hole and second alignment hole with different shapes may be provided, or the first alignment hole and second alignment hole may be provided such that there is no point symmetry positional relationship, in which the center of the steel sheets is the center of symmetry, therebetween.
- the first alignment hole and second alignment hole may be in positions which are the same distance from the center or may be in different positions.
- the number of alignment holes is not limited to two, rather, there may be three or more thereof.
- the rotating electrical device 100 which is used in a vehicle electric power steering apparatus, has been described as an example of an electronic device in the foregoing embodiments, the present invention is also applicable to rotating electrical devices (motors) for other purposes.
- the electronic device according to the present invention can be applied not only to a motor but also to other rotating electrical devices such as generators, and is also applicable to other electronic devices other than rotating electrical devices.
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Permanent Field Magnets Of Synchronous Machinery (AREA)
- Manufacture Of Motors, Generators (AREA)
- Iron Core Of Rotating Electric Machines (AREA)
Abstract
Description
- The present invention relates to a rotor and a rotor manufacturing method.
- For example, in a motor which is used in an automobile electric steering apparatus, motor torque pulsations are a primary cause of noise and vibration. One primary factor in torque pulsation is cogging torque.
- A rotor with a step skew structure is used to reduce cogging torque, as disclosed in JP 2014-236592 A, for example.
- The rotor core disclosed in JP 2014-236592 A has a step skew structure formed by laminating iron core material and a plurality of stepped cores, which have a plurality of permanent magnets provided around the iron core material, shifted by an amount corresponding to a skew angle. A rotor is configured by providing a through-hole, into which a rotating shaft is inserted, in the iron core material constituting the rotor core and by inserting the rotating shaft into the through-hole.
- In the rotor disclosed in JP 2014-236592 A, a key protruding in a radially inward direction from the inner peripheral surface of the rotor core is provided, and a plurality of key grooves for fixing the rotor core, each corresponding to the respective stepped cores, are provided on the outer peripheral surface of the rotating shaft in positions shifted by an amount corresponding to a skew angle. By laminating the plurality of stepped cores in order so that the key is fitted into the key grooves which correspond to the respective stepped cores of the rotating shaft, a rotor with a step skew structure is formed.
- The foregoing stepped cores can be formed by using adhesive to attach a plurality of permanent magnets around a cylindrical iron core material having a through-hole into which a rotating shaft is inserted, for example. Furthermore, the rotor core can be formed by laminating the plurality of stepped cores and press-fitting the rotating shaft into the through-hole by applying a load in the lamination direction.
- The end faces of the stepped cores are not necessarily flat due to dimensional errors of the iron core material and permanent magnets, respectively, rather, the iron core material may protrude further than the permanent magnets, or the permanent magnets may protrude further than the iron core material.
- When two stepped cores are laminated and the rotating shaft is press-fitted, same may be arranged and laminated such that end faces at which the permanent magnets of the two stepped cores protrude further than the iron core material, contact one another, for example. There has been a problem in that it is difficult to manufacture the rotor stably because the permanent magnets end up colliding and being damaged upon press-fitting the rotating shaft by applying a load in the lamination direction of the two stepped cores laminated in this state.
- In view of the foregoing issue, an object of the present invention is to provide a rotor and a rotor manufacturing method with which it is possible to obtain a rotor of stable quality.
- In order to achieve the foregoing object, a rotor according to one embodiment of the present invention includes a drive shaft, a first rotor core unit, and a second rotor core unit.
- The first rotor core unit includes a first iron core material having a through-hole into which the drive shaft is inserted, a plurality of first permanent magnets provided on the first iron core material, and a first reference surface at which the first iron core material and first permanent magnets are flush or at which the first iron core material protrudes further than the permanent magnets.
- The second rotor core unit includes a second iron core material having a through-hole into which the drive shaft is inserted, a plurality of second permanent magnets arranged on the side of the second iron core material, and a second reference surface at which the second iron core material and second permanent magnets are flush or at which the second iron core material protrudes further than the permanent magnets, the second rotor core unit being laminated in an axial direction on the first rotor core unit such that the first reference surface and the second reference surface contact each other, and being positioned shifted through a predetermined angle in the rotation direction of the drive shaft from the first rotor core unit.
- In order to achieve the foregoing object, a rotor manufacturing method according to one embodiment of the present invention includes forming an iron core material by laminating a plurality of rotor plates having a through-hole into which a drive shaft is inserted; attaching permanent magnets to the iron core material to form a rotor core unit having a reference surface at which the iron core material and the permanent magnets are flush or at which the iron core material protrudes further than the permanent magnets; and placing two of the rotor core units in an axial direction such that the reference surfaces thereof lie opposite each other, shifted in a circumferential direction, causing the reference surfaces of the two rotor core units to abut each other, and press-fitting the drive shaft into the through-hole by applying a load to the two rotor core units.
-
FIG. 1 is an exploded perspective view illustrating a configuration example of a rotating electrical device in which a rotor according to an embodiment of the present invention is installed; -
FIG. 2 is an essential part cross-sectional view of the rotating electrical device; -
FIG. 3 is a perspective view of the rotor according to an embodiment of the present invention; -
FIG. 4 is a perspective view of a rotor core unit constituting the rotor; -
FIGS. 5A and 5B are plan views of a rotor plate constituting an iron core material which constitutes the rotor core unit; -
FIG. 6 is a plan view of when two of the rotor plates are stacked together with the surface and back sides thereof oriented in opposite directions; -
FIGS. 7A to 7C are assembly process views illustrating steps for assembling the rotor core unit; -
FIG. 8 is a schematic cross-sectional view of a press fitting apparatus which is a view serving to illustrate a step of press-fitting a drive shaft in manufacturing the rotor core; -
FIG. 9 is a partial perspective view of the press fitting apparatus which is a view serving to illustrate a drive shaft press-fitting step; -
FIGS. 10A and 10B are schematic cross-sectional views of the rotor core unit; -
FIGS. 11A and 11B are schematic cross-sectional views of the rotor core; -
FIGS. 12A and 12B are a plan view of a rotor plate according to another embodiment and a plan view when two of the rotor plates are stacked together with the surface and back sides thereof oriented in opposite directions; and -
FIGS. 13A and 13B are diagrams to illustrate a method of manufacturing a rotor core which is a comparative example. - An embodiment of the present invention will be described hereinbelow with reference to the drawings.
- A rotating
electrical device 100 which includes a rotor according to one embodiment of the present invention is used as an automobile electric steering apparatus, for example, and is configured as a motor which applies a steering auxiliary force to a steering shaft. - <Configuration of Rotating Electrical Device>
-
FIG. 1 is an exploded perspective view illustrating a configuration example of rotatingelectrical device 100 according to one embodiment of the present invention, andFIG. 2 is an essential part cross-sectional view of rotatingelectrical device 100. - The rotating
electrical device 100 has acasing 10, acomponent package 20, amotor 30, abusbar unit 40, abearing holder 50, and a press-fit ring 60. - [Casing]
- The
casing 10 is formed with a cylinder-shaped (cylindrical) outline having anopening 11 and abottom portion 12 opposite theopening 11. Thecasing 10 is typically configured from a metal material such as aluminum die-cast or aluminum, and, as illustrated inFIG. 2 , accommodates themotor 30, thebusbar unit 40, and the like. - A
step portion 15 for supporting the perimeter of thebearing holder 50 which is inserted via theopening 11, is formed between thebottom portion 12 and opening 11 (seeFIG. 2 ). Thecasing 10 is provided between thebottom portion 12 andstep portion 15 and has amotor chamber 10M (seeFIG. 2 ) for accommodating therotor 32, described subsequently. - [Component Package]
- As illustrated in
FIG. 2 , thecomponent package 20 is held at the top end of thecasing 10 above themotor 30,busbar unit 40, andbearing holder 50. Thecomponent package 20 has a component mounting substrate 21 and aheat sink 23. - The component mounting substrate 21 of the present embodiment is a circuit board which includes various electronic devices (not illustrated) constituting an electronic control unit (ECU) of an electric power steering (EPS) apparatus. The electronic devices include a central processing unit (CPU), a memory, and the like. The component mounting substrate 21 is fixed to a heat sink (lid portion) 23 via a plurality of screw portions (not illustrated).
- The
heat sink 23 constitutes a lid portion which hermetically seals the interior of thecasing 10 by being fitted to the opening 11 in thecasing 10 via a seal ring S (seeFIG. 2 ). As illustrated inFIG. 1 , anexternal connection terminal 23 a, which electrically interconnects the component mounting substrate 21 and a power-supply unit which is not illustrated, is provided on the upper face of theheat sink 23. The perimeter of theheat sink 23 is provided with a plurality ofbrackets 23 b having a screw insertion hole, and is fastened with screws to a plurality offixing brackets 14 provided on the perimeter of theopening 11 in theheat sink 23 via thebrackets 23 b. - [Motor]
- The
motor 30 is accommodated in themotor chamber 10M in thecasing 10 as illustrated inFIG. 2 and has astator 31 and arotor 32. - The
stator 31 includes a plurality of teeth (stator cores) which are arranged in an annular shape inside thecasing 10 and coils (stator coils) which are wound around each of the plurality of teeth. The teeth are formed of a magnetic material and configured from a laminated body of a plurality of magnetic, rigid plates, for example. Thestator 31 is fixed to thecasing 10 by being fitted to the inner circumference of thecasing 10. To form three-phase magnetic coils with a U phase, V phase and W phase, both ends (not illustrated) of the coils are electrically connected to thebusbar unit 40. - The
rotor 32 has a drive shaft (rotating shaft) 321 which rotates about an axis (Z axis), and arotor core 322 which is attached to thedrive shaft 321. Thedrive shaft 321 is disposed along the axial center of thecasing 10 and press-fitted into a through-hole formed in the center of therotor core 322. Thedrive shaft 321 is rotatably supported in thecasing 10 via a bearing B1 (first bearing) and a bearing B2 (second bearing). Therotor core 322 has a plurality of magnetic poles arranged in a circumferential direction. Therotor 32 is disposed inside thestator 31 and causes thedrive shaft 321 to rotate on its axis under electromagnetic action with thestator 31. - The detailed configuration of the
rotor 32 will be described subsequently. - One end (the lower end in
FIGS. 1 and 2 ) of thedrive shaft 321 passes through thebottom portion 12 of thecasing 10 and has agear portion 323 at its tip. Thegear portion 323 meshes with a mating gear (not illustrated) linked to the steering shaft and transmits the rotation of thedrive shaft 321 to the steering shaft. - One bearing B1 (first bearing) is attached to the
bottom portion 12 of thecasing 10 and rotatably supports one end of thedrive shaft 321. The other bearing B2 (second bearing) rotatably supports the other end of thedrive shaft 321. - The bearing B2 is disposed between the
rotor core 322 and theheat sink 23 and is fixed to thecasing 10 via thebearing holder 50. The bearingholder 50 will be described in detail subsequently. - [Busbar Unit]
- The
busbar unit 40 has a plurality of busbars 41 formed of a conductive material and an electrically insulatedbusbar holder 42 which encloses the busbars 41 (seeFIG. 2 ). Thebusbar holder 42 is configured from an annular molded body, and the plurality of busbars 41 include a plurality of connectingterminals 41 a which protrude radially outward from the outer peripheral surface of thebusbar holder 42, and a plurality ofpower supply terminals 41 b which extend in an axial direction from the upper surface of thebusbar holder 42 and which correspond to a U phase, V phase, and W phase, respectively (seeFIG. 1 ). - The
busbar unit 40 is disposed inside thecasing 10 and is connected to the stator coils concentrically with thedrive shaft 321. The plurality of connectingterminals 41 a are electrically connected to one end of the U-phase, V-phase and W-phase stator coils, respectively, and the plurality ofpower supply terminals 41 b are electrically connected to aconnector component 22 on the component mounting substrate 21 which is fixed to the heat sink 23 (seeFIG. 2 ). - [Press-Fit Ring]
- The press-
fit ring 60 is annular, as illustrated inFIG. 1 . The press-fit ring 60 is press-fit via theopening 11 into thecasing 10 so as to sandwich the bearingholder 50 in the Z axis direction in conjunction with thestep portion 15. The press-fit ring 60 has an outerperipheral surface 60A which is press-fit to the inner peripheral surface of theopening 11, and asecond support face 60B which abuts the perimeter of the bearingholder 50. - The press-
fit ring 60 is formed of the same material as the casing 10 (aluminum die-cast or aluminum, or the like) or a material with a linear expansion coefficient on the order of the casing 10 (brass or a magnesium alloy, for example). - [Bearing Holder]
- The bearing
holder 50 serves to align and hold bearing B2 within thecasing 10, and is configured from a metallic-plate press-molded body. The bearingholder 50 according to the present embodiment is manufactured by deep-drawing and bending a metallic plate into a solid body shape. - The bearing
holder 50 is roughly disc-shaped, and provided in the center thereof is an axial hole through which thedrive shaft 321 passes. Abearing holding portion 502 for press-fitting and holding the second bearing B2 is provided in order to enclose the axial hole. - The
bearing holding portion 502 integrally holds the bearing B2 by means of a joining or fitting action with the outer race of the bearing B2. Here, an integral join with bearing B2 may also be obtained by caulking the open lower end portion of thebearing holding portion 502. - The bearing
holder 50 may be configured from a magnetic material or may be configured from a nonmagnetic material. As a result of the bearingholder 50 being configured from a magnetic material, a shielding effect whereby the electronic component on the component mounting substrate 21 is protected from the effects of an electromagnetic field generated by thestator 31 and therotor 32 is obtained. Such materials include SPCC (steel plate cold commercial), for example, but obviously is not limited to or by SPCC. - [Rotor Detailed Configuration]
-
FIG. 3 is a perspective view of therotor 32.FIG. 4 is a perspective view of arotor core unit 63 constituting therotor 32. Therotor 32 of the present embodiment is a rotor with a step skew structure. Therotor 32 is configured by laminating a plurality of independentrotor core units 63 which are shifted through predetermined angles in the circumferential direction. - As illustrated in
FIGS. 2 and 3 , therotor 32 has adrive shaft 321 and arotor core 322. Aninsertion hole 322 a through which thedrive shaft 321 passes is provided in the center of an approximatelycylindrical rotor core 322. - The
rotor core 322 is configured by laminating a plurality, two in the present embodiment, of independentrotor core units 63. In the present embodiment, arotor core unit 63 which is positioned on a lower level is called the lowerrotor core unit 63 a, and arotor core unit 63 which is positioned on an upper level is called the upperrotor core unit 63 b. - The lower
rotor core unit 63 a, which constitutes a first rotor core unit, has an aspect obtained by rotating (or inverting), in a vertically opposing direction, the upperrotor core unit 63 b, which constitutes a second rotor core unit. Otherwise, when the lowerrotor core unit 63 a and upperrotor core unit 63 b have the same configuration and there is no particular need to describe the upper and lower rotor core units distinctly, same are sometimes simply referred to as therotor core units 63. - In addition, when the
iron core material 8 andpermanent magnets 9 constituting therotor core units 63 are similar and the upper and lower rotor core units are described distinctly, the first iron core material is called lower iron core material 8 a, the second iron core material is called upperiron core material 8 b, the first permanent magnet is called lowerpermanent magnet 9 a, and the second permanent magnet is called upperpermanent magnet 9 b, but when there is no particular need for such distinction, same may be called theiron core material 8 andpermanent magnets 9. - The
rotor core units 63 have a roughly cylindrical shape, and include areference surface 61, and anopposite surface 62 which lies opposite the reference surface 61 (seeFIG. 8 , for example). - The details will be described subsequently, but, in the present embodiment, in a rotor manufacturing method which will be described subsequently, the side of a
jig 200, described subsequently, which contacts a workingsurface 201, serves as a reference surface during the assembly process of therotor core units 63. - The lower
rotor core unit 63 a and upperrotor core unit 63 b are laminated such that the reference surfaces 61 thereof abut each other. The lowerrotor core unit 63 a is disposed shifted, relative to the upperrotor core unit 63 b, through a predetermined angle (skew angle) in the rotation direction of the drive shaft 321 (in the circumferential direction of the rotor core unit). The cogging torque can accordingly be reduced. Although the foregoing shift is 12 degrees in the present embodiment, the present invention is not limited to or by this shift. The skew angle is suitably configured according to the shape and number of permanent magnets, and the like. - In the description hereinbelow, a
reference sign 61 a is sometimes assigned to the reference surface of the lowerrotor core unit 63 a which constitutes a first reference surface, and areference sign 61 b is sometimes assigned to the reference surface of the upperrotor core unit 63 b which constitutes a second reference surface. Furthermore, theopposite surface 62 opposite thereference surface 61 is sometimes described hereinbelow by assigning a reference sign 62 a to the opposite surface of the lowerrotor core unit 63 a and by assigning areference sign 62 b to the opposite surface of the upperrotor core unit 63 b. -
FIG. 5A is a plan view of asteel sheet 81 which is a rotor plate constituting theiron core material 8. -
FIG. 5B is a plan view of when the surface and back sides of thesteel sheet 81 inFIG. 5A are oriented in opposite directions. -
FIG. 6 is a plan view of when twosteel sheets 81 are stacked together with the surface and back sides thereof oriented in opposite directions. - The
rotor core units 63 have aniron core material 8 which is fixed to the outer periphery of thedrive shaft 321 and rotates together with thedrive shaft 321, and a plurality ofpermanent magnets 9 which are attached at equal intervals around the outer periphery of theiron core material 8. Sixpermanent magnets 9 are provided in the present embodiment. - The
iron core material 8 is configured by laminating a plurality of thesteel sheets 81 illustrated inFIG. 5A , as illustrated inFIG. 2 . - As illustrated in
FIGS. 5A and 5B , thesteel sheets 81 have a through-hole 84 in the center of which thedrive shaft 321 is inserted, afirst alignment hole 82, and asecond alignment hole 83. All of the holes have a circular planar shape. - The
iron core material 8 is formed by laminating the plurality ofsteel sheets 81 such that the respective through-holes 84, first alignment holes 82 and second alignment holes 83 are stacked on top of each other. - As a result of laminating the plurality of
steel sheets 81, the respective through-holes 84 are contiguous, and the through-hole 841 (seeFIG. 4 ) of theiron core material 8 is formed. - A
reference sign 841 a is assigned to the through-hole provided in the iron core material 8 a of the lowerrotor core unit 63 a, and areference sign 841 b is assigned to the through-hole provided in theiron core material 8 b of the upperrotor core unit 63 b (seeFIG. 9 ). - Moreover, by laminating the two
rotor core units holes iron core material 8 of the respectiverotor core units insertion hole 322 a in which thedrive shaft 321 is inserted is formed. - Furthermore, by laminating the plurality of
steel sheets 81, the respective first alignment holes 82 are contiguous, and afirst alignment hole 821, which passes through theiron core material 8, is formed. Similarly, the respective second alignment holes 83 of the laminated plurality ofsteel sheets 81 are contiguous, and asecond alignment hole 831, which passes through theiron core material 8, is formed (seeFIG. 4 ). - Reference signs 821 a and 831 a are assigned to the first alignment hole and second alignment hole, respectively, which are provided in the iron core material 8 a of the lower
rotor core unit 63 a. Reference signs 821 b and 831 b are assigned to the first alignment hole and second alignment hole, respectively, which are provided in theiron core material 8 b of the upperrotor core unit 63 b (seeFIG. 9 ). Furthermore, when there is no particular need to distinguish between the upper and lower rotor core units, the foregoing alignment holes are sometimes referred to as thefirst alignment hole 821 and thesecond alignment hole 831. - As illustrated in
FIGS. 5A and 5B , thesteel sheets 81 have an approximately circular shape. Sixprotrusions 85 are provided at equal intervals on the periphery of thesteel sheets 81. - When the
iron core material 8 is formed by stacking together a plurality of thesteel sheets 81, six linear protrusions which extend parallel to the axial direction of the sixdrive shafts 321 are formed by theprotrusions 85 on the side of the cylindricaliron core material 8. Furthermore,permanent magnets 9 are arranged in the gaps formed between the adjacent linear protrusions. - The
first alignment hole 82 andsecond alignment hole 83 both have planar shapes which are circles of the same diameter. In the present embodiment, thefirst alignment hole 82 andsecond alignment hole 83 are not positioned on the same circumferences centered on thesteel sheet 81, rather, same are located at different distances from the center of thesteel sheet 81. - More specifically, the
first alignment hole 82 andsecond alignment hole 83 both have a circular shape with a diameter which is 1.5 mm in size, and the distance between the center of thefirst alignment hole 82 and the center of thesteel sheet 81 is 8 mm, and the distance between the center of thesecond alignment hole 83 and the center of thesteel sheet 81 is 7.75 mm. In addition, an angle of 128° is formed between a straight line joining the center of thesteel sheet 81 to thefirst alignment hole 82 and a straight line joining the center of thesteel sheet 81 to thesecond alignment hole 83. Furthermore, the numerical values of these dimensions are not limited to the numerical values appearing here. - The
steel sheet 81 has afirst face 811 and asecond face 812 which are opposite each other.FIG. 5A is a plan view of when thefirst face 811 is made the upper surface.FIG. 5B is a plan view of when thesecond face 812 is made the upper surface. - As illustrated in
FIGS. 5A and 5B , even when thesteel sheet 81 illustrated inFIG. 5A is reversed, the respective positions of thesteel sheet 81, thefirst alignment hole 82, and thesecond alignment hole 83 illustrated inFIG. 5B do not coincide with each another. - That is, the
first alignment hole 82 andsecond alignment hole 83 are formed to not have the same shape when the surface and back sides of thesteel sheet 81 are oriented in opposite directions. Furthermore, the circular through-hole 84 which is provided in the center of thesteel sheets 81 is provided to afford coincidence when twosteel sheets 81 are stacked together with the surface and back sides thereof oriented in opposite directions. - A
steel sheet 81 a is a steel sheet for when thesecond face 812 illustrated inFIG. 5B is made the upper surface. Asteel sheet 81 b is a steel sheet for when thefirst face 811 illustrated inFIG. 5A is made the upper surface. - In the example illustrated in
FIG. 6 , thesteel sheet 81 a is located below thesteel sheet 81 b. - Furthermore,
FIG. 6 illustrates the positional relationship, in therotor 32 illustrated inFIG. 3 , between asteel sheet 81 which constitutes theiron core material 8 b of the upperrotor core unit 63 b and thesteel sheet 81 which constitutes the iron core material 8 a of the lowerrotor core unit 63 a. The lowerrotor core unit 63 a and upperrotor core unit 63 b are arranged shifted through a predetermined angle, which is 12° in the present embodiment, in the direction of rotation of thedrive shaft 321. - In
FIG. 6 , thesteel sheet 81 constitutingiron core material 8 b of the upperrotor core unit 63 b corresponds to thesteel sheet 81 b on the upper surface of which thefirst face 811 is located. Thesteel sheet 81 constituting iron core material 8 a of the lowerrotor core unit 63 a corresponds to thesteel sheet 81 a on the upper surface of which thesecond face 812 is located. - In
FIG. 6 ,reference signs steel sheet 81 b which is disposed on the upper side, andreference signs steel sheet 81 a which is disposed on the lower side. - As illustrated in
FIG. 6 , when twosteel sheets 81 are stacked together with the surface and back sides thereof oriented in opposite directions in a state where the centers coincide, the alignment holes thereof do not simultaneously coincide with each other. In addition, the two alignment holes do not coincide with each other even when onesteel sheet 81 is rotated in a circumferential direction. - Accordingly, in the
rotor 32 illustrated inFIG. 3 , because the lowerrotor core unit 63 a and upperrotor core unit 63 b are arranged positioned vertically opposing each other, the alignment holes 821 and 831 do not coincide with each other. - Six
permanent magnets 9 are arranged at equal intervals in the circumferential direction of theiron core material 8. Furthermore, the number ofpermanent magnets 9 is not limited to this quantity, rather, therotor core units 63 may have seven or more permanent magnets arranged side by side in a circumferential direction or may have any number, from two to five, of permanent magnets. - The
rotor 32 is formed by press-fitting and securing thedrive shaft 321 in theinsertion hole 322 a in therotor core 322. The surface, of thedrive shaft 321, which corresponds to theinsertion hole 322 a (configuration denoted by thereference sign 321 a inFIG. 8 , described subsequently) is knurled, and the surface has a textured shape. The diameter of theinsertion hole 322 a is slightly smaller than the diameter of thedrive shaft 321. Therotor core 322 is fixed to thedrive shaft 321 by press-fitting thedrive shaft 321 in theinsertion hole 322 a. - The lower
rotor core unit 63 a and upperrotor core unit 63 b are arranged such that thereference surface 61 a andreference surface 61 b abut each other. - The reference surfaces 61 are flat surfaces. Here, flat surfaces also include, in addition to an aspect where the end face of the
iron core material 8 and the end faces of thepermanent magnets 9 are completely flush, an aspect in which, due to an error during assembly of therotor core unit 63, the end face of theiron core material 8 protrudes 0.2 mm or less in the axial direction further than the end faces of thepermanent magnets 9. - [Rotor Manufacturing Method]
- A rotor manufacturing method will be described next.
- The
rotor 32 is mainly manufactured through a step of assembling therotor core units 63 and a press-fitting step of press-fitting thedrive shaft 321 inside the two laminatedrotor core units 63. Each step will be described hereinbelow. - [Rotor Core Unit Assembly Step]
- The step of assembling the
rotor core units 63 will now be described usingFIGS. 7A to 7C . -
FIGS. 7A to 7C are views of the step of assembling therotor core units 63. - (Assembly Jig Configuration)
- First, an
assembly jig 200, illustrated inFIG. 7A , which is used when assembling therotor core units 63 will be described first. - As illustrated in
FIG. 7A , theassembly jig 200 is mounted on a flat surface. Thejig 200 is used for alignment so that, when forming theiron core material 8 obtained by laminating a plurality ofsteel sheets 81, the plurality ofsteel sheets 81 are not laminated with a skew. Furthermore, thejig 200 is used for alignment so that the respective end faces of theiron core material 8 andpermanent magnets 9 are aligned upon fastening the plurality ofpermanent magnets 9 to the periphery of theiron core material 8. - The
jig 200 has aworkbench 202 which has aflat working surface 201, and twoalignment pins workbench 202. Thealignment pin 212 is provided to correspond to thealignment hole 82 of thesteel sheets 81, and thealignment pin 213 is provided to correspond to thealignment hole 83. - (Description of Assembly Step)
- The assembly step will be described next.
- As illustrated in
FIG. 7A , thesteel sheets 81 are mounted on theworkbench 202 by passing the corresponding alignment pins 212 and 213 provided in thejig 200 through the alignment holes 82 and 83, respectively, of thesteel sheets 81. Accordingly, thesteel sheets 81 are mounted such that thefirst face 811 of thesteel sheets 81 is the upper surface, and thesecond face 812 is positioned on the workingsurface 201 side. - As illustrated in
FIG. 7A , a predetermined number ofsteel sheets 81 are laminated on thejig 200. - As mentioned earlier, the alignment holes 82 and 83 are provided in the
steel sheets 81 so as to not coincide with each other when twosteel sheets 81 are stacked together with the surface and back sides thereof oriented in opposite directions. Thus, as illustrated inFIG. 7A , thesteel sheets 81 can be laminated reliably, with thefirst face 811 serving as the upper surface, by placing thesteel sheets 81 according to the alignment pins 212 and 213 provided on thejig 200. For example, thesteel sheets 81 can be laminated reliably such that thesecond face 812 is positioned on the workingsurface 201 side, even when thesteel sheets 81 are to be mounted with the surface and back sides thereof oriented in opposite directions, because the alignment pins 212 and 213 cannot pass through the alignment holes 82 and 83. - The
iron core material 8 is formed by laminating and stacking a predetermined number ofsteel sheets 81. Theiron core material 8 has a through-hole 841, afirst alignment hole 821, and asecond alignment hole 831, which each pass through theiron core material 8. - Thereafter, as illustrated in
FIG. 7B , thepermanent magnets 9 are fastened to the periphery of theiron core material 8 in a state where theiron core material 8 is mounted on theworkbench 202. Thereupon, by sticking thepermanent magnets 9 to theiron core material 8 so that one end face of thepermanent magnets 9 contacts the workingsurface 201, one end face of thepermanent magnets 9 and one end face of theiron core material 8 can be aligned on the same surface. - The
rotor core units 63 are thus assembled as illustrated inFIG. 7C . The surface, of therotor core unit 63, which contacts the workingsurface 201 isreference surface 61, and the surface opposite thereference surface 61 isopposite surface 62. - The
reference surface 61 is a flat surface. Here, flat surfaces also include, in addition to an aspect where thesecond face 812 of thesteel sheet 81 in the lowest position which constitutes theiron core material 8 and one end face of thepermanent magnets 9 are completely flush, an aspect in which, due to an error during assembly of therotor core unit 63, one end face of the iron core material 8 (corresponds here to thesecond face 812 of thesteel sheet 81 in the lowest position which constitutes theiron core material 8 during assembly) protrudes 0.2 mm or less further than the one end face of thepermanent magnets 9. - [Driving Shaft Press-Fitting Step]
- A drive shaft press-fitting step in which two
rotor core units 63, assembled as mentioned earlier, are laminated and thedrive shaft 321 is press-fit will be described next usingFIGS. 8 and 9 . - (Configuration of Press Fitting Apparatus)
- First, the configuration of a press
fitting apparatus 7 which is employed in the drive shaft press-fitting step will be described. -
FIG. 8 is a schematic cross-sectional view of a pressfitting apparatus 7 which is a view serving to illustrate a driving shaft press-fitting step. The through-hole 841 andalignment holes rotor core units FIG. 8 in order to make the drawing clearer. -
FIG. 9 is a partial perspective view of the pressfitting apparatus 7.FIG. 9 is a diagram illustrating the positional relationships betweenalignment holes rotor core units alignment pins - As illustrated in
FIGS. 8 and 9 , the pressfitting apparatus 7 has alower support portion 71 constituting a first support portion and anupper support portion 72. - The
lower support portion 71 has alower pedestal 711 and alower support base 712 constituting a first support base. - The
lower pedestal 711 has a larger planar shape than thelower support base 712 and supports thelower support base 712. - The
lower support base 712 is installed on thelower pedestal 711. A firstalignment support pin 7122 and a secondalignment support pin 7123 are provided on thelower support base 712. Thelower support base 712 is configured to enable the lowerrotor core unit 63 a to be installed and mainly supports the iron core material 8 a part of the lowerrotor core unit 63 a. -
Insertion holes drive shaft 321, are provided in thelower pedestal 711 andlower support base 712, respectively. - The first
alignment support pin 7122 and secondalignment support pin 7123 which are provided on thelower support base 712 are arranged in positions enabling insertion into thefirst alignment hole 821 a and the second alignment hole 831 a, respectively, of the lowerrotor core unit 63 a on the lower surface of which the opposite surface 62 a is located and on the upper surface of which reference surface 61 a is located. - The
upper support portion 72 has anupper pedestal 721 and anupper support base 722 constituting a second support base. - The
upper pedestal 721 has a larger planar shape than theupper support base 722 and supports theupper support base 722. - The
upper support base 722 is installed on theupper pedestal 721. A firstalignment support pin 7222 and a secondalignment support pin 7223 are provided on theupper support base 722. Theupper support base 722 is configured to enable the upperrotor core unit 63 b to be installed and mainly supports aniron core material 8 b part of the upperrotor core unit 63 b. -
Insertion holes drive shaft 321, are provided in theupper pedestal 721 andupper support base 722, respectively.Insertion hole 7221, which is provided in theupper support base 722, is a through-hole, andinsertion hole 7211, which is provided in theupper pedestal 721, is an insertion hole with a bottom portion prescribing an insertion limit of thedrive shaft 321. - The first
alignment support pin 7222 and secondalignment support pin 7223 which are provided on theupper support base 722 are arranged in positions enabling insertion into thefirst alignment hole 821 b and thesecond alignment hole 831 b, respectively, of the upperrotor core unit 63 b on the upper surface of which theopposite surface 62 b is located and on the lower surface of which thereference surface 61 b is located. - As illustrated in
FIG. 9 , the positions of the first and second alignment support pins 7222 and 7223 of theupper support base 722 coincide with the positions of the first and second alignment support pins 7122 and 7123 when thelower support base 712 has been vertically inverted and rotated in a circumferential direction in the drawing. - The
upper support base 722 andlower support base 712 are arranged such that the upperrotor core unit 63 b and lowerrotor core unit 63 a are shifted in a circumferential direction through a skew angle. - Thus, by configuring the positions of the first and second alignment support pins 7222 and 7223 on the
upper support base 722, therotor core unit 63 b assembled in the foregoing assembly step can be installed on theupper support base 722 by making theopposite surface 62 b the upper surface and thereference surface 61 b the lower surface. - Likewise, by configuring the positions of the first and second alignment support pins 7122 and 7123 on the
lower support base 712 as described earlier, therotor core unit 63 a assembled in the foregoing assembly step can be installed on thelower support base 712 by making the opposite surface 62 a the lower surface and thereference surface 61 a the upper surface. - As mentioned earlier, by using
rotor core units 63 which employsteel sheets 81 having shapes in which the alignment holes 82 and 83 do not coincide when twosteel sheets 81 are stacked together with the surface and back sides thereof oriented in opposite directions, and by using a pressfitting apparatus 7 which hassupport bases rotor core units 63 for which, at first glance, it is hard to identify onereference surface 61 from the other, if therotor core units fitting apparatus 7, installation is possible such that the reference surfaces 61 of the upperrotor core unit 63 b and lowerrotor core unit 63 a are reliably arranged opposite each other. - Thus, the rotor core units can be arranged in the press
fitting apparatus 7 without confirming the reference surfaces 61, and workability improves. Moreover, because two rotor core units can be laminated such that the reference surfaces 61 thereof reliably lie opposite each other, it is possible to obtain arotor 32 of a quality which is always stable. - (Description of Press-Fitting Step)
- A step of press-fitting the
drive shaft 321 which employs the foregoing pressfitting apparatus 7 will be described next usingFIGS. 8 and 9 . - First, as illustrated in
FIG. 9 , the lowerrotor core unit 63 a is installed on thelower support base 712 such that the alignment pins 7122 and 7123 are inserted into the respective alignment holes 821 a and 831 a. - As illustrated in
FIGS. 8 and 9 , the lowerrotor core unit 63 a is installed such thatreference surface 61 a is located on an upper side and the opposite surface 62 a is located on a lower side. The through-hole 841 a of the lowerrotor core unit 63 a and theinsertion hole 7121 of thelower support base 712 and theinsertion hole 7111 of thelower pedestal 711 communicate. - Similarly, the upper
rotor core unit 63 b is installed on theupper support base 722 such that the alignment pins 7222 and 7223 are inserted into therespective alignment holes - The upper
rotor core unit 63 b is installed such thatreference surface 61 b is located on a lower side and theopposite surface 62 b is located on an upper side. The through-hole 841 b of the upperrotor core unit 63 b and theinsertion hole 7221 of theupper support base 722 and theinsertion hole 7211 of theupper pedestal 721 communicate. - Thus, in the press-fitting step, the upper
rotor core unit 63 b and lowerrotor core unit 63 a are arranged such that the reference surfaces 61 thereof lie opposite each other. - Thereafter, as illustrated in
FIG. 8 , thedrive shaft 321 is provisionally inserted in the lowerrotor core unit 63 a. Thedrive shaft 321 is provisionally inserted as a result of an area below theknurled surface 321 a passing through the respective insertion holes in the lowerrotor core unit 63 a, thelower support base 712, and thelower pedestal 711. - Thereafter, the
upper support portion 72 is moved downward and thelower support portion 71 is moved upward, thereby press-fitting thedrive shaft 321 into the upperrotor core unit 63 b and the lowerrotor core unit 63 a. A load is applied to the upperrotor core unit 63 b and lowerrotor core unit 63 a during the press fitting of thedrive shaft 321. - The
drive shaft 321 is press-fit into the upperrotor core unit 63 b and lowerrotor core unit 63 a, thereby forming therotor 32. - Here, in the assembled
rotor core units 63, theopposite surface 62 which lies opposite thereference surface 61 which is a flat surface is designed to be a flat surface, but unevenness can inevitably be generated as a result of intrinsic dimensional errors, or the like, in theiron core material 8 andpermanent magnets 9. - For example, as per the
rotor core unit 63 illustrated inFIG. 10A , at theopposite surface 62 which lies opposite thereference surface 61 located on the workingsurface 201 side of theassembly jig 200 during assembly, theiron core material 8 may protrude further than the other end face of thepermanent magnet 9 and, as illustrated inFIG. 10B , the other end face of thepermanent magnet 9 may protrude further than theiron core material 8. Thus, unevenness can inevitably be generated in theopposite surface 62 relative to thereference surface 61 which is a flat surface. - The unevenness which is generated in the
opposite surface 62 of therotor core unit 63 is unevenness where the difference between thepermanent magnets 9 andiron core material 8 is less than 1 mm, for example, and, at first glance, it is difficult to identify which of the surfaces of therotor core unit 63 is thereference surface 61. - As described earlier, in the step of press-fitting the
drive shaft 321, thedrive shaft 321 is press-fit by applying a load in an axial direction to the two laminatedrotor core units 63. - In a case where the
rotor 32 is manufactured by using therotor core unit 63, illustrated inFIG. 10B , in which thepermanent magnets 9 protrude further than theiron core material 8 at theopposite surface 62, if the press-fitting step is performed with theopposite surfaces 62 of tworotor core units FIG. 13B , a load is applied in an axial direction to the tworotor core units permanent magnets 9 collide with each other. Thepermanent magnets 9 are formed by fragile, sintered bodies, and hence thepermanent magnets 9 are damaged in the press-fitting step. - However, in the present embodiment, because, as described earlier, two
rotor core units rotor 32 stably without thepermanent magnets 9 colliding with each other and being damaged. - For example, even when the
rotor core units FIG. 11A , haveopposite surfaces 62 at which theiron core material 8 protrudes further than thepermanent magnets 9, are laminated, because same are laminated with the reference surfaces 61 thereof, which are flat surfaces, abutting each other, thepermanent magnets 9 are not damaged as a result of colliding. - Similarly, even when the
rotor core units FIG. 11B , haveopposite surfaces 62 at which thepermanent magnets 9 protrude further than theiron core material 8, are laminated, because same are laminated with the reference surfaces 61 thereof, which are flat surfaces, abutting each other, thepermanent magnets 9 are not damaged as a result of colliding. - Furthermore, as illustrated in
FIG. 13A , if surfaces at which theiron core material 8 protrudes more than thepermanent magnet 9 are arranged opposite each other, because thepermanent magnets 9 do not collide with each other, damage to the permanent magnets is not generated in the drive shaft press fitting step. In a case where theiron core material 8 protrude further than thepermanent magnets 9 and where two rotor core units are laminated by arranging these surfaces opposite each other, a gap is generated between thepermanent magnets 9 of the upperrotor core unit 63 b and thepermanent magnets 9 of the lowerrotor core unit 63 a. This gap is preferably 0.4 mm or less, for example. - Moreover, in the present embodiment, because the upper
rotor core unit 63 b and lowerrotor core unit 63 a, which constitute therotor 32, can be assembled by means of thesame assembly jig 200, there is no need to assemble upper and lower rotor core units by means of separate assembly jigs, and hence workability is favorable. - The rotor 32 of the present embodiment includes a drive shaft 321; a lower rotor core unit (first rotor core unit) 63 a which includes a lower iron core material (first iron core material) 8 a having a through-hole 841 a into which the drive shaft 321 is inserted, a plurality of lower permanent magnets (first permanent magnets) 9 a provided on the lower iron core material (first iron core material) 8 a, and a first reference surface 61 a at which the lower iron core material (first iron core material) 8 a and lower permanent magnets (first permanent magnets) 9 a are flush or at which the lower iron core material (first iron core material) 8 a protrudes further than the lower permanent magnets (first permanent magnets) 9 a; and an upper rotor core unit (second rotor core unit) 63 b which includes an upper iron core material (second iron core material) 8 b having a through-hole 841 b into which the drive shaft 321 is inserted, a plurality of upper permanent magnets (second permanent magnets) 9 b provided on the upper iron core material (second iron core material) 8 b, and a second reference surface 61 b at which the upper iron core material (second iron core material) 8 b and upper permanent magnets (second permanent magnets) 9 b are flush or at which the upper iron core material (second iron core material) 8 b protrudes further than the upper permanent magnets (second permanent magnets) 9 b, the upper rotor core unit (second rotor core unit) 63 b being laminated in the axial direction on the lower rotor core unit (first rotor core unit) 63 a such that the first reference surface 61 a and second reference surface 61 b contact each other, and being positioned shifted through a predetermined angle in the rotation direction of the drive shaft 321 from the lower rotor core unit (first rotor core unit) 63 a.
- Furthermore, the method of manufacturing the
rotor 32 of the present embodiment includes: forming aniron core material 8 by laminating a plurality of steel sheets (rotor plates) 81 having a through-hole 841 into which adrive shaft 321 is inserted; attachingpermanent magnets 9 to theiron core material 8 to form arotor core unit 63 having areference surface 61 at which theiron core material 8 and thepermanent magnets 9 are flush or at which theiron core material 8 protrudes further than thepermanent magnets 9; and placing two of therotor core unit 63 in an axial direction such that the reference surfaces 61 thereof lie opposite each other, shifted in a circumferential direction, causing the reference surfaces 61 of the tworotor core units 63 to abut each other, and press-fitting thedrive shaft 321 into the through-hole 841 by applying a load to the tworotor core units 63. - According to the
rotor 32 and the method of manufacturing therotor 32 thus configured, therotor 32 is formed by way of lamination such that the reference surfaces 61 of the tworotor core units 63 abut each other, and therefore thepermanent magnets 9 of eachrotor core unit 63 do not collide and are not damaged, thereby enabling arotor 32 of stable quality to be obtained. - Embodiments of the present invention have been described hereinabove, but it goes without saying that the present invention is not limited to the foregoing embodiments alone, rather, various additional modifications can be made.
- For example, although, by way of an example in the foregoing embodiment, the
first alignment hole 82 andsecond alignment hole 83, which are at different distances from the center of thesteel sheet 81, are provided as the alignment holes provided in thesteel sheets 81, the present invention is not limited to such an example. - The alignment holes may be provided such that the alignment holes do not coincide with each other when two steel sheets are stacked together with the surface and back sides thereof oriented in opposite directions.
- As an example, as per the
steel sheet 181 illustrated inFIGS. 12A and 12B , afirst alignment hole 182 and asecond alignment hole 183, which are circles of different diameters, are provided, and thefirst alignment hole 182 andsecond alignment hole 183 may be provided such that there is no point symmetry positional relationship, in which the center of thesteel sheets 181 is the center of symmetry, therebetween. In this case, thefirst alignment hole 182 andsecond alignment hole 183 may be in positions which are the same distance from the center or may be in different positions. - In this case, different thicknesses may be used for the two alignment pins provided on the assembly jig which is used when assembling the rotor core units and for the two alignment pins provided on each support base used in the press fitting apparatus, respectively.
- In addition, as a further example, a first alignment hole and second alignment hole with different shapes may be provided, or the first alignment hole and second alignment hole may be provided such that there is no point symmetry positional relationship, in which the center of the steel sheets is the center of symmetry, therebetween. In this case, the first alignment hole and second alignment hole may be in positions which are the same distance from the center or may be in different positions.
- Furthermore, the number of alignment holes is not limited to two, rather, there may be three or more thereof.
- Moreover, although the rotating
electrical device 100, which is used in a vehicle electric power steering apparatus, has been described as an example of an electronic device in the foregoing embodiments, the present invention is also applicable to rotating electrical devices (motors) for other purposes. In addition, the electronic device according to the present invention can be applied not only to a motor but also to other rotating electrical devices such as generators, and is also applicable to other electronic devices other than rotating electrical devices. - The present application claims a right of priority on the basis of Japanese Patent Application No. 2018-235324 which was published at the Japan Patent Office on Dec. 17, 2018, the entire contents of which are incorporated by reference in present specification.
Claims (5)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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JP2018-235324 | 2018-12-17 | ||
JP2018235324A JP7228182B2 (en) | 2018-12-17 | 2018-12-17 | Rotor and rotor manufacturing method |
JPJP2018-235324 | 2018-12-17 |
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US20200195105A1 true US20200195105A1 (en) | 2020-06-18 |
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DE102021123150A1 (en) | 2021-09-07 | 2023-03-09 | Nidec Corporation | Electric motor with magnetic shielding integrated into the end shield |
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JP2017163757A (en) * | 2016-03-10 | 2017-09-14 | アイシン・エィ・ダブリュ株式会社 | Rotor and method of manufacturing the rotor |
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JPH0612936B2 (en) | 1983-12-01 | 1994-02-16 | 株式会社日立製作所 | Method for manufacturing stator core for electric motor |
JP3487180B2 (en) * | 1998-06-15 | 2004-01-13 | 株式会社日立製作所 | Permanent magnet type synchronous rotating electric machine rotor |
JP4035994B2 (en) * | 2002-01-10 | 2008-01-23 | 松下電器産業株式会社 | Rotating machine |
JP4855123B2 (en) * | 2006-04-05 | 2012-01-18 | 株式会社三井ハイテック | Manufacturing method of rotor laminated core |
JP5170878B2 (en) * | 2008-03-12 | 2013-03-27 | アイチエレック株式会社 | Permanent magnet rotating machine rotor |
JP5309630B2 (en) * | 2008-03-14 | 2013-10-09 | パナソニック株式会社 | Permanent magnet embedded motor |
JP5231082B2 (en) * | 2008-05-09 | 2013-07-10 | 東芝産業機器製造株式会社 | Rotating electrical machine rotor |
JP5581013B2 (en) * | 2009-06-23 | 2014-08-27 | 株式会社三井ハイテック | Rotor core |
EP2325980B2 (en) * | 2009-11-23 | 2018-11-07 | ABB Schweiz AG | Rotor disk and assembly method |
JP2014150626A (en) | 2013-01-31 | 2014-08-21 | Sanyo Denki Co Ltd | Rotor for permanent magnet motor, method of manufacturing rotor for permanent magnet motor, and permanent magnet motor |
JP2014236592A (en) | 2013-06-03 | 2014-12-15 | 株式会社ジェイテクト | Rotor for dynamo-electric machine and manufacturing method therefor |
JP2017022854A (en) | 2015-07-09 | 2017-01-26 | トヨタ自動車株式会社 | Manufacturing method for rotary electric machine rotor |
JP6240365B1 (en) * | 2016-04-13 | 2017-11-29 | 黒田精工株式会社 | Manufacturing method of magnet embedded core |
JP2017212867A (en) * | 2016-05-19 | 2017-11-30 | 三星電子株式会社Samsung Electronics Co.,Ltd. | Magnet-embedded motor and compressor using the same |
-
2018
- 2018-12-17 JP JP2018235324A patent/JP7228182B2/en active Active
-
2019
- 2019-12-03 US US16/701,624 patent/US11611269B2/en active Active
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JP2017163757A (en) * | 2016-03-10 | 2017-09-14 | アイシン・エィ・ダブリュ株式会社 | Rotor and method of manufacturing the rotor |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102021123150A1 (en) | 2021-09-07 | 2023-03-09 | Nidec Corporation | Electric motor with magnetic shielding integrated into the end shield |
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CN111327134A (en) | 2020-06-23 |
US11611269B2 (en) | 2023-03-21 |
JP2020099109A (en) | 2020-06-25 |
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